Bastille Day is celebrated every year on July 14 in France and other French-speaking countries around the world. The holiday celebrates the beginning of the French Revolution, which occurred over 200 years ago.

Soon after, Trump also said that he would postpone his vice presidential announcement in light of the attack. Originally, Trump was scheduled to announce his running mate on Friday at 11 a.m. in Manhattan.

In light of the horrible attack in Nice, France, I have postponed tomorrow's news conference concerning my Vice Presidential announcement.

In an interview with Fox News Channel’s “The O’Reilly Factor,” Trump said, “This is war.” He explained if he’s elected president he would ask Congress for a declaration of war on the Islamic State, which he called a “cancer.” He also said NATO should be used “for a purpose.”

O’Reilly said, “I believe it’s a world war now. We are in a world war scenario. It’s no longer just isolated ISIS attacks. Do you agree with that?”

“I certainly do,” Trump replied. “And I’ve been saying it for a long time. It’s out of control. We have a president that doesn’t want to call it what it is. And you know you look at World Trade Center, you look at San Bernardino, you look at Paris, 130 people killed and so many injured in Paris from that attack, and you look at Orlando. It’s out of control. And Bill, unless we get strong and really strong and very, very smart leadership, it’s only going to get worse.”

Donald Trump: Use NATO to destroy ISIS; this is warPresumptive GOP presidential nominee weighs in on 'The O'Reilly Factor' following the terror attack in Nice, France2016-07-15T02:16:29.000Z

Trump has responded to other recent shootings and attacks on social media. Most recently, he shared a message of prayers and condolences last week after five Dallas police officers were killed in the deadliest incident for law enforcement in the United States since 9/11. His message had a softer tone than his previous social media posts.

Prayers and condolences to all of the families who are so thoroughly devastated by the horrors we are all watching take place in our country

In a statement following the Instanbul attack, he said that the “whole world is stunned and horrified.”

“The terrorist threat has never been greater,” Trump stated. “Our enemies are brutal and ruthless and will do anything to murder those who do not bend to their will. We must take steps to protect America from terrorists, and do everything in our power to improve our security to keep” America safe.”

During a recent rally in Ohio Trump said the Istanbul attack proved that the United States “better get smart” to protect itself.

“As you know we had another suicide bombing, Istanbul, Turkey,” he said. “Many, many people killed. Many, many people injured. Folks, there’s something going on that’s really, really bad. Alright. It’s bad. And we better get smart, and we better get tough or we’re not going to have much of a country left, OK? It’s bad. Terrible.”

Trump faced a backlash on Twitter after tweeting this response to the deadly Orlando shooting in June:

Appreciate the congrats for being right on radical Islamic terrorism, I don't want congrats, I want toughness & vigilance. We must be smart!